import sys
sys.setrecursionlimit(10**7)
def input(): return sys.stdin.readline().rstrip()


def main():
    if int(input()) >= 30:
        print('Yes')
    else:
        print('No')


if __name__ == '__main__':
    main() import sys sys sys.setrecursionlimit(10**7) sys.setrecursionlimit sys setrecursionlimit 10**7 10 7 def input(): return sys.stdin.readline().rstrip() input def main():
    if int(input()) >= 30:
        print('Yes')
    else:
        print('No') main if int(input()) >= 30:
        print('Yes')
    else:
        print('No') int(input()) >= 30 int(input()) int input() input 30 print('Yes') print 'Yes' print('No') print 'No' if __name__ == '__main__':
    main() __name__ == '__main__' __name__ '__main__' main() main def main():
    if int(input()) >= 30:
        print('Yes')
    else:
        print('No') def main():
    if int(input()) >= 30:
        print('Yes')
    else:
        print('No') main def input(): return sys.stdin.readline().rstrip() def input(): return sys.stdin.readline().rstrip() input
import sys
sys.setrecursionlimit(10**7)
def input(): return sys.stdin.readline().rstrip()


def main():
    if int(input()) >= 30:
        print('Yes')
    else:
        print('No')


if __name__ == '__main__':
    main()